The position that many in the mainstream tend to have is a belief that the Missoula Floods were a series of events that occurred over a period of millions of years.
The story goes something like this:
- during an ice-age
- the Northern ice cap on the planet — about a mile or two thick
- part of the glacier melted
- the meltwater was restrained by the same glacier
- sufficient water was released to wear-away basalt
- 150 coulees were washed out of the basalt bedrock
- So the glacier was warmed enough to melt
Actually, from the current incarnation of the wiki article on the topic:
After each ice dam rupture, the waters of the lake would rush down the Clark Fork and the Columbia River, flooding much of eastern Washington and the Willamette Valley in western Oregon. After the rupture, the ice would reform, creating Glacial Lake Missoula again
No argument from me about the very broad time-frame; during the ice age. And, there’s no argument about the concept of ice melting… but that’s very much the limit of plausible.
How does a glacier exist in both a solid and liquid state? …for sufficient time for that much water to accumulate? …without re-freezing? …without the glacier itself simply melting away beneath it?
How would that much water exist in a state of thermal equilibrium for water to exist as both a liquid (in a reservoir) and solid (forming an ice-dam) simultaneously?
How much water would be needed to wear away basalt? That would most certainly need to be liquid. I get that, but it would be surrounded by ice?
The concept of the “Missoula Floods” would also tend to suggest that all of the coulees tended to originate from a single point (okay, an area) in the Northern Rocky Mountain range — through which all of the water passed.
I do wonder, what proxies have we collected that may corroborate the Missoula Floods hypothesis?